Notice of Quekett’s Treatise on the Microscope. 69 
suggest that should Mr. Quekett’s work reach a third edition, he 
may safely affirm Richmond to be in the United States of North 
America, leaving the particular State in which it is located, to be 
determined by future geographical researches. 
he chief advances made in microscopical apparatus, since the 
objects. This is common ground on which all microscopists meet, 
and no better evidence can be offered of the improvements in 
microscopes of late years, than the gradual adoption of more dif_i- 
cult tests, for the same focus object-glasses, Only a few years 
ago, the Navicula Hi pocampus was sent to this country from 
England as the test par excellence, and within the last six months 
that “severe test” thoroughly defined by one of Mr. Spencer’s 
half-inch objectives. cag 
r. Quekett has not only furnished no description of any new 
test; but as before stated, he has omitted the account of the Nav. 
pencerli, which was a severer test than any he has described ; 
hot that we object to the omission of that description, or the-plate, 
or both were grossly erroneous as to measurements and general 
Structure, To be sure, in the appendix we are informed in a short 
what they must look for in the new tests, both of which have 
now been before the microscopic world for more than two years. 
no plate might well have taken the place of Mr. De la Rue’s 
Scale of Amathusia Horsfieldii,” which, in addition to its being 
altogether inappropriate to such a work, had been already else- 
where published : besides, after the “ faithful delineation” of the 
N. Sp liin the first edition, we are not inclined to attach 
